R. F. Craig (Auth.)-Soil Mechanics_ Solutions Manual-Springer US (1992)

Soil Mechanics Fifth Edition Salutions Manual

Soil Mechanics Fifth Edition Solutions Manual R.F. Craig Department of Civil Engineering University of Dundee, UIC

SPRINGER-SCIENCE+BUSINESS MEDIA. B.V.

First edition 1992

© 1992 R.F. Craig Originally published by Chapman & Hall in I992 Typeset in 10/12 pt Times by Pure Tech Corporation, India ISBN 978-0-412-47230-5

ISBN 978-1-4899-3772-8 (eBook)

DOI 10.1007/978-1-4899-3772-8 Apart from any fair dealing for the purposes of research or private study, or criticism or review, as permitted under the UK Copyright Designs and Patents Act, 1988, this publication may not be reproduced, stored, or transmitted, in any form or by any means, without the prior permission in writing of the publishers, or in the case of reprographic reproduction only in accordance with the terms of the licences issued by the Copyright Licensing Agency in the UK, or in accordance with the terms of licences issued by the appropriate Reproduction Rights Organization outside the UK. Enquiries concerning reproduction outside the terms stated here should be sent to the publishers at the London address printed on this page. The publisher makes no representation, express or implied, with regard to the accuracy of the information contained in this book and cannot accept any legal responsibility or liability for any errors or omissions that may be made. A catalogue record for this book is available from the British Library Library of Congress Cataloging-in-Publication data available

Contents 1 2 3 4 5 6 7 8 9

Basic Characteristics of Soils Seepage Effective Stress Shear Strength Stresses and Displacements Lateral Earth Pressure Consolidation Theory Bearing Capacity Stability of Slopes

1 7 15

23 29 35 49 59 71

Author's note

In order not to short-circuit the learning process it is vital that the reader should attempt the problems before referring to the solutions in this manual.

Basic Characteris tics of Soils

1.1 British system Soil E consists of 98% coarse material (31% gravel size; 67% sand size) and 2% fines. It is classified as SW: well-graded gravelly SAND or, in greater detail, weil graded slightly silty very gravelly SAND. Soil F consists of 63% coarse material (2% gravel size; 61% sand size) and 37% non-plastic fines (i.e. between 35% and 65% fines), therefore the soil is classified as MS: sandy SILT. Soil G consists of 73% fine material (i.e. between 65% and I 00% fines) and 27% sand size. The liquid Iimit is 32 and the plasticity index is 8 (i.e. 32- 24), plotting marginally below the A-line in the ML zone on the plasticity chart. Thus the classification is ML: SILT (M-SOIL) of low plasticity. (The plasticity chart is given in Fig. 1.6.) E

E

00 90 80 70 60 50 40 30 20 10 0 CLAY

0.001

C\i

v

/

/

~

V

V

I

E ~

I

I

E

F

[/

V SILT MEDIUM COARSE

0.01

SAND

FINE

MEDIUM I COARSE

0.1 Particle size (mm)

Fig Ql.l

E

t.. .Y

!--"' FINE

cD

C\J

'/

I V

E E ~

(')

V

V

H

G

E E

E E

:1 0

C\J

~

BSSieves

E

:1

:1

FINE

GRAVEL COBBLES MEDIUM COARSE

10

100

1

__________~ ____AL ____c_s_:_S_O_LU_T_I_O_N_S_MANU ~-2--~~ ~~___________s_o_I_L_M_E_c_arum Soil H consists of 99% fine material (58% clay size; 47% silt size). The liquid limit is 78 and the plasticity index is 4 7 (i.e. 78- 31), plotting above the A-line in the CV zone on the plasticity chart. Thus the classification is CV: CLAY of very high plasticity.

Unified system Soil Eis classified as SW, a well-graded gravelly sand. More than 50% of the soil is of sand size and the fine-grained fraction is less than 5%. The following values are obtained from the particle size distribution curve: D 10 =0.16mm; D 3o=0.53mm; D60 = 1.40mm 1. 40 = 8.8 cu = 0.16

Cz =

(equation 1.1)

= 1.25 0.532 1.40x0.16

(equation 1.2)

i.e.Cu>6 and l